Electrophysiology catheters are commonly-used for mapping electrical activity in the heart. Various electrode designs are known for different purposes. In particular, catheters having basket-shaped electrode arrays are known and described, for example, in U.S. Pat. Nos. 5,772,590, 6,748,255 and 6,973,340, the entire disclosures of each of which are incorporated herein by reference, for use within a chamber of a patient's heart or similar region.
Basket catheters typically have an elongated catheter body and a basket-shaped electrode assembly mounted at the distal end of the catheter body. The basket assembly has proximal and distal ends and comprises a plurality of spines distributed around the circumference and connected at their proximal and distal ends. Each spine comprises at least one electrode, and typically several electrodes arrayed along the length of the spine. The basket assembly has an expanded arrangement wherein the spines bow radially outwardly and a collapsed arrangement wherein the spines are arranged generally along the axis of the catheter body. The collapsed arrangement facilitates introduction of the basket-shaped electrode assembly through the patient's vasculature while the expanded arrangement is intended to bring the electrodes arrayed along the spines into contact with the tissue defining the chamber in which the assembly is deployed.
It is desirable that a basket-shaped electrode assembly be capable of detecting as much information as possible as rapidly as possible. For example, it is desirable to capture, such as during a single beat, a wide picture of the electrical function of a region where the electrode assembly is deployed, such as the left or right atrium. As an illustration, fibrillation may present in a number of complex manners, including both paroxysmal as well as persistent atrial fibrillation and is not well understood. Attempts to characterize the conditions have employed a number of theories, including wavelet analysis, rotors and Shannon Entropy to identify the sources of perturbing electrical signals to facilitate quick and targeted ablation in such patients. As such, an expansive and accurate reflection of the electrical function in an affected region would confer considerable advantage when applying these and other techniques.
Conventional basket-shaped electrode assemblies are generally spherical and may be offered in a number of different sizes to help match the assembly to the particular anatomy of the patient. Nevertheless, such assemblies may not provide an optimal conformation to the anatomy of the chamber in which they are deployed. For example, some number of spines in a conventional basket-shaped electrode assembly may be in contact with openings in the chamber, such as the mitral valve. Accordingly, the signals collected from the electrodes on those spines do not contribute any meaningful information towards the analysis for finding the source of atrial fibrillation. The other spines, even if not positioned over an opening, may not be in optimal contact with the tissue defining the chamber, and suffer from degradation in the quality of information collected from their electrodes. Further, by seeking to come into contact with as much of the interior surface of the atrium or other chamber, convention basket-shaped electrode assemblies may be configured to assume a single, optimal shape that is generally spherical. Although different overall sizes may be provided, the inability to change the shape of the basket limits the ability of the assembly to have optimal contact with the atrial wall.
Accordingly, it would be desirable to provide a basket-shaped electrode assembly that distributes spines asymmetrically to allow the assembly to be positioned in an orientation that maximizes the number of spines in contact with a desired region of the chamber in which the assembly is deployed. It would also be desirable to prove a basket-shaped electrode assembly capable of assuming a variety of deployed, expanded arrangements to increase the number of electrodes that may be brought into contact with the chamber walls. The techniques of this disclosure as described in the following materials satisfy these and other needs.